Need something to do with 2 guitarists

okay so we are gonna perform, i don't want to cover a song since we don't have a singer, bass player, or a drummer. So what could we do? i was thinking of something like a guitar duel, or playing some riffs while harmonizing. The song that popped up in my head was Mr.Crowley. anyways, do you guys know any songs with some nice harmonizing licks.